How can i enable it so that players can aim pitch from -90 to +90 instead of just from 0 to 90?

I had finally come up with a mod idea but i hit this brick wall. please don't tell me again that it can't be done.

The player himself, no. and I'm assuming you mostly mean lasers.

However, with a little code magic on a few specific weapons, you
can off-set the angle to.. perhaps -30, and then fire it accordingly.
eg. target is 5 degrees down, aim at +25.

It has been done several times already in a few mods, with only
minor angle glitches happen at certian positions.
note: see lasermod Bended style lasers.

It perhaps could be added to the ToDo ideas list, but since the
majority of "none mod' weapons won't use it, it may be treated
with indifference by many.

It looks like that can work.

Is there some way you could make the pitch angle redirect =
(angle - 45) * 2

this would provide a full 180 degrees by using only every other degree of the 180.

Or a "Low-beam" laser that used (elevation * -1)?
That would be lovely..
Presetting the off-set is the most we can do for now, calculations
aren't allowed in the XML.
That type of calculated scripting is being tested in the alpha of
v42 but not funtional yet.